Of great importance for the meat processing industry in its modern form is to undertake a grading of meat in regard to the quality thereof and in regard to the yield to be expected for specific products already in the processing lines of slaughtering operations. For this purpose, for example, at defined sites or regions in the carcasses of slaughtered animals, also referred to as animal carcasses, or the halves thereof, which, suspended from a tube track, are usually passed through a processing line, it is known to make a cut that does not completely sever the carcass and to inspect at least one of the cut surfaces thereby obtained or, in individual cases, to even inspect both of the cut surfaces.
Originally, the assessment of corresponding cut surfaces occurred as part of the visual inspection by personnel trained for this purpose. An approach of this kind has become known, for example, in connection with the grading of the rib eye in the carcasses of slaughtered cattle. In this case, a person undertaking the grading assesses a cut surface produced beforehand by making a cut between the 12th rib and the 13th rib of a side of beef of a slaughtered animal, in particular in regard to the marbling and the size of the rib eye. However, the result of such a grading occurring by a human is naturally more or less subjective in nature.
In order to obtain more objective and insofar more precise results as well as for reasons of processing economy, a transition has been made to undertaking the meat grading by way of a software-based processing of images that are acquired from a carcass of a slaughtered animal, or parts thereof, or of cut surfaces of the aforementioned kind by means of electronic image acquisition systems. By means of image processing devices equipped with corresponding software for this purpose, it is hereby possible, on account of the different lightness and/or the different colors of individual image regions, to draw a conclusion about the distribution of the tissue-compartmented bones, meat, and fat as well as, by the use of rules deposited in the system for this purpose, to undertake classifications of the meat in regard to its quality and the yields to be expected for individual meat products.
A method of this kind is described, for example, by US 2003/0072472 A1, in particular in regard to the grading of the rib eye in the case of beef. The solution described in said publication hereby also proceeds from a cut made in the region between the 12th rib and the 13th rib in the side of beef of a slaughtered animal. Fed through the processing line suspended at one of the extremities thereof, the carcass gapes open in the cut region, so that, in any case, at least one of the two cut surfaces resulting from the cut can be recorded with imaging technology by means of at least one camera. The recorded image or images of the cut surface are then fed to a corresponding image processing device for processing with the aim of evaluating the meat.
In accordance with the solution described in the cited publication, the image acquisition occurs by means of an optical measurement head or sensor head that is guided by hand. The sensor head is wedge-shaped in design and can therefore be introduced easily into the gaping region of the cut made in the carcass. Through a camera or a comparable optical sensor unit contained in the measurement head or sensor head, images of the cut surface to be evaluated are recorded at the angle dictated by, among other things, the geometry of the measurement head or sensor head.
Fundamentally, by means of the previously described system, relatively good grading results are obtained. A certain source of error and accordingly a weak point, however, is represented by the not insubstantial variation in the manual positioning of the measurement head or sensor head. In consequence thereof and in spite of fitting assisting auxiliary devices onto the measuring head, distortions in the image acquisition occur and hence errors in the meat grading result, which are undesired on account of the existing strong cost pressure in the meat processing industry. In order to be able to meet even better the interest of the meat processing industry in a precise meat grading, therefore, there is required a solution that minimizes the variance in the image acquisition of carcasses of slaughtered animals and hence makes it possible to provide, as a basis for the subsequent electronic processing, images of a constantly high quality.